JPH11159623A - Metal gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reform a coating of a layered metal plate constituting, a metal gasket and maintain a seal effect of a fold back part enveloping the periphery of a combustion chamber hole. SOLUTION: In a metal gasket interposed in a joint surface between a cylinder head 10 and a cylinder block 11 of an internal combustion engine, a soft sub-plate 2 of prescribed gasket shape is layered in an elastic base board 1 of prescribed gasket shape constituting the metal gasket, a molybdenum coating film 5 is applied to a surface of the sub-plate 2, a rubber coating film 7 is applied to the base board 1, and a fold back part 3 placing a non-coating surface 6 of the sub-plate 2 in an inner side is formed in the periphery of a combustion chamber hole, so as to make the fold back part in maximum thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket in which a metal gasket inserted into a mating surface between a cylinder head and a cylinder block of an internal combustion engine maintains a sealing effect at a folded portion surrounding a combustion chamber hole. About.

[0002]

2. Description of the Related Art An example of a conventional metal gasket inserted between a cylinder head and a cylinder block of an internal combustion engine will be described with reference to FIG.

In the metal gasket shown in FIG. 1, a soft sub-plate 21 is laminated on the upper surface of an elastic substrate 20 formed in a predetermined shape according to the shape of the mating surface of the cylinder head 10 and the cylinder block 11, and 21 engine combustion chamber 1
3 at the combustion chamber hole 22 surrounding the turning portion 2
By sandwiching the periphery of the combustion chamber hole of the substrate 20 with 3, the thickness of the folded portion 23 is made thicker than other laminated portions.

Therefore, in the gap between the cylinder head 10 and the cylinder block 11, the folded portion 23 of the sub-plate 21 has a wedge effect by the stopper and exerts a strong surface pressure.

Further, cooling water holes or oil holes 25 and 26 are formed in the substrate 20 and the sub plate 21 in correspondence with the cooling water passage or the oil passage 12 of the engine, and the cooling water holes or the oil holes 25 and 26 are formed. Step bead 2 along the inner circumference of
0a and 21a are formed, and the substrate 20 and the sub-plate 21 are formed.
The stepped beads 20b and 21b are formed along the outer periphery of, so that the sealing performance by the bead load is exerted.

Further, rubber coatings 24 are applied to both surfaces of the substrate 20 and the outer surface of the sub-plate 21. Such a rubber coating 24 absorbs the roughness of the metal surface of the cylinder head 10 and the cylinder block 11 (cutter damage due to grinding) or absorbs the roughness of the metal surface between the substrate 20 and the sub-plate 21. It is like that.

In the above configuration, when the cylinder head 10 and the cylinder block 11 are bolted together,
Loads f1, f2, f3, f of the step bead
Although the loads F1 and F2 larger than 4 are applied, the roughness of the metal surfaces of the cylinder head 10 and the cylinder block 11 is absorbed by the wedge effect of the folded portion 23, the bead load of the step bead, and the elasticity of the rubber coating 24, Or substrate 2
Roughness of the metal surface between the 0 and the sub-plate 21 is absorbed to prevent blow-through of the combustion gas.

[0008]

However, the cylinder head 10 and the cylinder block 11 are subject to an increase and decrease in the axial force of the tightening bolts of the cylinder head 10 and the cylinder block 11 caused by the repetition of the operation and stop of the engine. In addition, a gas explosion generated in the combustion chamber 13 causes a phenomenon in which a gap between the two is continuously expanded and contracted.

At this time, the folded portion 23 having the largest load is used.
If the upper and lower surfaces are hit, it becomes impossible to cope with the thickness maintenance of the rubber coating 24 of the folded portion 23, and it becomes impossible to absorb the above-mentioned roughening of the metal surface of the cylinder head 10 and the cylinder block 11. However, there is a problem that the combustion gas passes through the rough portion.

The rubber coating 24 provided on the sub-plate 21
Is exposed to the combustion chamber 13 of the engine through the combustion chamber hole 22, the high-temperature gas at the time of the combustion explosion attacks the rubber coating 24, and the metal surface of the cylinder head 10 and the metal surface of the cylinder block 11 are separated from each other. There is also a problem that the rubber film 24 cannot be coped with the displacement of the surfaces due to thermal strain and thermal expansion, and the rubber coating 24 peels off from the metal surface of the sub-plate 21 and blow-through of combustion gas occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has an improved coating of a laminated metal plate constituting a metal gasket to improve a sealing effect of a folded portion surrounding the periphery of a combustion chamber hole. It is an object to provide a metal gasket adapted to be maintained.

[0012]

SUMMARY OF THE INVENTION In order to solve the above problems, a metal gasket according to the present invention is a metal gasket inserted into a mating surface of a cylinder head and a cylinder block of an internal combustion engine. A flexible sub-plate of a predetermined gasket shape is laminated on a gasket-shaped elastic substrate, a molybdenum coating is applied to the surface of the sub-plate, and a rubber coating is applied to the substrate. By forming the folded portion, the folded portion has the maximum thickness.

Further, an auxiliary plate independent of the substrate may be provided inside the folded portion of the sub-plate, so that the folded portion of the sub-plate may sandwich the auxiliary plate.

Further, the folded portion of the sub-plate may sandwich the periphery of the combustion chamber hole of the substrate.

Further, the sub-plate may be formed thicker than the substrate, and may be folded around the combustion chamber hole without holding a metal plate other than the sub-plate inside the folded portion of the sub-plate. .

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a metal gasket according to a first embodiment of the present invention. FIG. 2 is a sectional view of a metal gasket according to a second embodiment of the present invention. FIG. 3 is a sectional view of a metal gasket according to a third embodiment of the present invention. FIG. 4 is a sectional view of a metal gasket according to a fourth embodiment of the present invention.

(Embodiment 1) As shown in FIG. 1, a metal gasket of the present embodiment is interposed on a mating surface of a cylinder head 10 and a cylinder block 11 of an internal combustion engine. This metal gasket is formed of an elastic substrate 1 having a predetermined shape corresponding to the shape of the mating surface of the cylinder head 10 and the cylinder block 11.
And a soft metal sub-plate 2 to form a laminated metal plate. A folded portion 3 is formed on the combustion chamber hole side of the sub-plate 2 so as to form a primary seal against the combustion gas from the combustion chamber hole 12. is there.

In this embodiment, the sub-plate 2 is formed to be thinner than the substrate 1, and the combustion chamber hole side of the substrate 1 extends to the vicinity of the outer periphery of the folded portion 3 of the sub-plate 2. A ring-shaped auxiliary plate 4 independent of the substrate 1 is provided, and the folded portion 3 of the sub-plate 2 sandwiches the auxiliary plate 4, so that the folded portion 3 has a maximum thickness in the laminated metal plate.

In such a configuration, the substrate 1 and the auxiliary plate 4 are provided intermittently, but the folded portion 3 provided on the sub-plate 2 also functions as a grommet,
This has an advantage that a thin gasket having a two-layer structure of the substrate 1 and the sub-plate 2 can be formed as compared with the conventional configuration in which the grommets are independently provided.

Further, cooling water holes or oil holes 8, 9 corresponding to the cooling water passages or oil passages 12 of the engine are formed in the substrate 1 and the sub-plate 2, and these cooling water holes or oil holes 8, 9 are formed. By forming the step beads 1a and 2a along the inner circumference of the substrate 1, a secondary seal is formed by the bead load, and further, the step beads 1a and 2a are formed along the outer circumference of the substrate 1 and the sub-plate 2.
By forming b and 2b, sealing performance against cooling water or lubricating oil due to bead load is exhibited.

Further, a molybdenum coating 5 is applied to the surface of the sub-plate 2, and the back surface is an uncoated surface 6, and the auxiliary plate 4 is sandwiched by the folded portion 3 having the uncoated surface 6 inside. It is.

Further, a metal plate other than the sub-plate 2, that is, the substrate 1
A rubber coating 7 is applied to both surfaces of the sub-plate 2 so that the upper rubber coating 7 faces the uncoated surface 6 of the sub-plate 2 and the lower rubber coating 7 faces the upper surface of the cylinder block 11.

In such a configuration, when the cylinder head 10 and the cylinder block 11 are bolted together, the stepped beads 1a, 1b, 2
Loads F1 and F2 larger than loads f1, f2, f3 and f4 of a and 2b act to exert a wedge effect as a stopper to form a primary seal, thereby preventing combustion gas blow-through and the like. be able to.

Further, when grinding the lower surface of the cylinder head 10 and the upper surface of the cylinder block 11, there is a rough metal surface due to tool mark flaws (cutter flaws due to grinding). If attention is paid only to the filling of the roughness, it is preferable to apply a rubber coating to the surface of the sub-plate 2 and fill the roughness of the metal surface by the elasticity of the rubber coating as in the related art. In order to eliminate the disadvantage of the rubber coating, that is, the peeling of the rubber coating caused by the hitting at the folded portion 3 where the surface pressure is the strongest and the displacement of the metal surface between the cylinder head 10 and the cylinder block 11, the surface of the sub-plate 2 is coated with a molybdenum coating. It was set to 5.

Since the fine molybdenum coating 5 has fine irregularities in the form of particles on the surface thereof, if the molybdenum coating 5 is pressed evenly on a metal surface having a roughened unevenness, the fine molybdenum coating 5 can be made finer. The unevenness is filled so as to bite into the roughness of the metal surface, and the sealing performance can be exhibited.

According to the present invention, the molybdenum coating 5 is applied to the surface of the outermost soft sub-plate 2 of the laminated metal plate in order to effectively utilize the fine irregularities existing in the molybdenum coating 5. The repulsive force of the rubber coating 7 is transmitted to the sub-plate 2 as a damper, and at the same time, the sub-plate 2 is formed of a soft metal plate having good conformability.
The molybdenum film 5 fills the rough surface of the lower surface of the cylinder head 10 to prevent the blow-through of the combustion gas, and further ensures the perfect sealing performance of cooling water and lubricating oil.

Further, since the molybdenum coating 5 of the sub-plate 2 faces the combustion chamber 13, the coating is not damaged by the high-temperature combustion gas as in the prior art.

In the metal gasket of FIG. 1, the sub-plate 2 is laminated on the upper surface of the substrate 1 so as to face the cylinder head 10. The same effect can be exhibited even if the user faces 11.

By applying a sealant of several microns to the surface of the molybdenum coating 5, the sealing performance of the cylinder head 10 or the cylinder block 11 against tool mark flaws can be improved without impairing the sealing performance of the combustion gas. Can also.

(Embodiment 2) As shown in FIG. 2, a metal gasket of this embodiment has a flexible sub-plate 2
And a molybdenum coating 5 is applied to the surface of the sub-plate 2, and the folded portion 3 is formed around the combustion chamber hole of the sub-plate 2 so that the non-coated surfaces 6 inside the sub-plate 2 are in direct contact with each other. It is.

In such a configuration, the combustion chamber hole side of the substrate 1 extends to the vicinity of the outside of the folded portion 3 of the sub-plate 2, but since the sub-plate 2 is formed to be thicker than the substrate 1, the folded portion is formed. 3 is the maximum thickness of the laminated metal plate.

As in the first embodiment, rubber plates 7 are applied to metal plates other than the sub-plate 2, ie, both sides of the substrate 1, and step beads 1a, 1b, 2a are formed on both the substrate 1 and the sub-plate 2. , 2b
Is provided.

Therefore, in this embodiment, too, Embodiment 1
Similarly to the above, a molybdenum coating 5 is applied to the surface of the outermost flexible sub-plate 2 of the laminated metal plate, and the repulsive force of the rubber coating 7 of the elastic substrate 1 is transmitted to the sub-plate 2 as a damper. Is formed of a soft metal plate having good conformability, the molybdenum coating 5 of the sub-plate 2 fills the rough surface of the lower surface of the cylinder head 10 to prevent the combustion gas from flowing through, and furthermore, complete the cooling water and the lubricating oil. A good sealing performance can be ensured.

(Embodiment 3) In the metal gasket of this embodiment, as shown in FIG. 3, a thin flexible substrate 1 is laminated on an upper surface of an elastic substrate 1, and a molybdenum coating is formed on the surface of the sub-plate 2. 5, a folded portion 3 is formed around the combustion chamber hole so as to sandwich the periphery of the combustion chamber hole of the substrate 1 with the uncoated surface 6 of the sub-plate 2 inside.

Also in this embodiment, as in the first embodiment, rubber coatings 7 are applied to both sides of the
Since the step beads 1a, 1b, 2a, and 2b are provided on both the sub-plate 2 and the sub-plate 2, this embodiment has the same effect as described above.

Further, in this embodiment, since the rubber coating 7 provided on the substrate 1 exists inside the folded portion 3 with respect to the combustion chamber 13, the influence of the combustion gas in the combustion chamber 13 can be avoided. It is possible.

As shown in FIG. 3, a portion of the substrate 1 which is in contact with the non-coating surface 6 inside the folded portion 3 is a non-rubber coating surface 7a so as to avoid the influence of surface pressure on the rubber coating. You may. As a processing method for this, there is a method in which a rubber coating 7 is applied to the entire surface of the substrate 1 and a portion corresponding to the non-rubber coating surface 7a is peeled off by a water jet or the like.

(Embodiment 4) In the metal gasket of this embodiment, as shown in FIG. 4, a thin flexible substrate 1 is laminated on the upper surface of an elastic substrate 1, and a molybdenum coating is formed on the surface of the sub-plate 2. 5, a folded portion 3 is formed around the combustion chamber hole 12 so as to sandwich the periphery of the combustion chamber hole of the substrate 1 with the uncoated surface 6 of the sub-plate 2 inside.

In this embodiment, no bead is provided on the sub-plate 2 and a bead 1c and a step bead 1b having a semicircular arc section are formed on the substrate 1, and the bead shape is different from that of the above embodiment. However, similar effects can be exerted.

In the first to fourth embodiments,
Although the substrate 1 other than the sub-plate 2 is provided as a single layer, it may be configured as a multilayer. In this case, regardless of the configuration of the laminated metal plate, the sub-plate 2 provided with the molybdenum coating 5 on the outermost side is laminated so that the molybdenum coating 5 faces the lower surface of the cylinder head 10 or the upper surface of the cylinder block 11. What should I do?

[0042]

As described above, in the metal gasket of the present invention, a flexible sub-plate is laminated on an elastic substrate, a molybdenum coating is applied to the surface of the sub-plate, and a rubber coating is applied to the substrate. By forming a folded portion around the combustion chamber hole where the non-coated surface of the sub-plate is on the inside, the folded portion has the maximum thickness, so that the folded portion has a maximum surface pressure and exhibits a wedge effect. Then, the molybdenum coating on the surface is filled so as to bite against the roughness of the metal surface of the cylinder head and the cylinder block, and a strong 1
Make the next seal.

Also, at a portion other than the folded portion, the repulsive force of the rubber film of the elastic substrate is transmitted to the soft sub-plate as a damper, and the molybdenum film of the sub-plate fills the rough metal surface of the cylinder head or the cylinder block. As a result, it is possible to prevent blow-through of the combustion gas and to ensure perfect sealing of cooling water and lubricating oil.

Further, in the folded portion having the maximum surface pressure, the portions facing the metal surfaces of the cylinder head and the cylinder block are all made of molybdenum coating.
Even if a tapping occurs during a combustion explosion, it is not crushed like a rubber coating, and can exhibit high-proof stress sealing performance over a long period of time.

Further, according to the structure of the present invention, since the sub-plates are provided continuously, a thin metal gasket can be formed by a small number of metal plates, and the coating facing the combustion chamber is molybdenum. Because of the coating, the durability against high-temperature combustion gas is also improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a metal gasket according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a metal gasket according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a metal gasket according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a metal gasket according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a conventional metal gasket.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 1a, 1b ... Substrate bead 1c ... Substrate arc-shaped bead 2 ... Sub-plate 2a, 2b ... Sub-plate step bead 3 ... Folding part 4 ... Auxiliary plate 5 ... Molybdenum coating 6 ... Uncoated surface 7 ... Rubber coating 7a ... Non-rubber coating surface 8 ... Cooling water hole or oil hole of substrate 9 ... Cooling water hole or oil hole of sub-plate 10 ... Cylinder head 11 ... Cylinder block 12 ... Engine cooling water passage or oil passage 13 ... Combustion chamber

Claims (4)

[Claims] A metal gasket interposed between a mating surface of a cylinder head and a cylinder block of an internal combustion engine, wherein a flexible sub-plate having a predetermined gasket shape is laminated on an elastic substrate having a predetermined gasket shape constituting the metal gasket; By applying a molybdenum coating to the surface of the plate and applying a rubber coating to the substrate, and forming a folded portion around the combustion chamber hole of the sub-plate with the non-coated surface of the sub-plate being inside, the folded portion is maximized. Metal gasket characterized by thickness. 2. An auxiliary plate independent of the substrate is provided inside a folded portion of the sub-plate so that the folded portion of the sub-plate sandwiches the auxiliary plate. 2. The metal gasket according to 1. 3. The metal gasket according to claim 1, wherein the folded portion of the sub-plate sandwiches around a combustion chamber hole of the substrate. 4. The method according to claim 1, wherein the auxiliary plate is formed thicker than the substrate.
2. The metal gasket according to claim 1, wherein the metal plate other than the sub-plate is folded around the combustion chamber hole without sandwiching a metal plate other than the sub-plate inside the folded portion of the sub-plate.